Submission #556876

#	Time	Username	Problem	Language	Result	Execution time	Memory
556876		Hanksburger	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	801 ms	972932 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define si short int
#define pii pair<si, si>
#define fi first
#define se second
pii dir[4]={{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
vector<pii > vec[2];
string a[4000];
si n, m;
int ans;
void dfs(pii u)
{
	char x=a[u.fi][u.se];
	a[u.fi][u.se]='.';
	for (pii i:dir)
	{
		pii v=u;
		v.fi+=i.fi;
		v.se+=i.se;
		if (v.fi>=0 && v.fi<n && v.se>=0 && v.se<m && a[v.fi][v.se]!='.')
		{
			if (a[v.fi][v.se]==x)
				dfs(v);
			else
				vec[(ans&1)^1].push_back(v);
		}
	}
}
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> m;
	for (si i=0; i<n; i++)
		cin >> a[i];
	vec[0].push_back({0, 0});
	while (vec[ans&1].size())
	{
		for (pii u:vec[ans&1])
			dfs(u);
		vec[ans&1].clear();
		ans++;
	}
	cout << ans;
	return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70